Midtarsal Joint 2026: Chopart Joint Anatomy and Pathology

The midtarsal joint (transverse tarsal joint or Chopart joint) is the collective term for two articulations in the midfoot that together form a functional transverse unit: the talonavicular joint (between the head of the talus and the navicular bone) and the calcaneocuboid joint (between the calcaneus and the cuboid bone). Named after French surgeon Francois Chopart, who described disarticulation at this level, the midtarsal joint controls the transition between rearfoot motion and forefoot motion, acting as a mechanical amplifier of subtalar pronation and supination into forefoot position changes — and it is the anatomical location where the foot can be locked into a rigid lever or unlocked for flexibility depending on the phase of gait. Understanding midtarsal joint mechanics is essential for interpreting flat foot deformity, midfoot arthritis, and the biomechanical consequences of subtalar pathology on forefoot loading.

Midtarsal Joint: Anatomy, Axes, and Biomechanical Function

Component	Anatomy	Motion	Biomechanical Role
Talonavicular joint	Ball-and-socket articulation between the rounded head of the talus and the concave posterior surface of the navicular; coplanar with the calcaneocuboid joint; surrounded by the spring ligament (plantar calcaneonavicular ligament) inferiorly	Approximately 40-60° of total motion across all planes; dorsal-plantar, medial-lateral, and rotational; the most mobile joint in the midfoot	Primary determinant of midfoot position; talonavicular joint motion governs arch height — navicular dorsal displacement = arch flattening; spring ligament failure (PTT dysfunction) allows navicular to drop, producing acquired flat foot
Calcaneocuboid joint	Saddle-shaped articulation between the anterior calcaneus and the posterior cuboid; less mobile than talonavicular; stabilized by long and short plantar ligaments, bifurcate ligament, and calcaneocuboid ligament	Limited — primarily anteroposterior motion (compression-distraction); less rotational than talonavicular; more important for lateral column stability than motion	Lateral column stabilizer during push-off; the long plantar ligament from calcaneus to metatarsal bases crosses the calcaneocuboid joint and is a primary lateral arch support; calcaneocuboid joint contact pressure increases with excessive pronation and lateral column shortening
Midtarsal joint locking mechanism (Elftman)	The two joint axes of the midtarsal joint (longitudinal and oblique) are parallel during pronation (foot unlocked) and non-parallel (divergent) during supination (foot locked). When axes are parallel, motion is possible along a common axis; when divergent, the joint mechanically locks	During pronation: midtarsal joint axes become parallel → midfoot unlocks → forefoot accommodates to surface. During supination: axes diverge → midtarsal joint locks → foot becomes rigid lever for propulsion	Explains why a pronated foot is flexible and accommodating but poor at propulsion, while a supinated foot is rigid and efficient for push-off but poor at shock absorption — the fundamental trade-off in foot biomechanics governed by the midtarsal joint locking mechanism
Spring ligament (plantar calcaneonavicular ligament)	Thick ligamentous complex running from the sustentaculum tali of the calcaneus to the plantar-medial surface of the navicular; supports the head of the talus from below like a hammock; part of the medial ankle ligament complex	Provides static support to the talar head and navicular during weight-bearing; works with the PTT dynamically; fibrocartilaginous central portion withstands compressive load of talar head	Spring ligament rupture or attenuation = acquired adult flat foot; PTT dysfunction leads to spring ligament overload and eventual failure; spring ligament reconstruction is now included in many flat foot surgical reconstructions (Cotton osteotomy + spring ligament repair)

Midtarsal Joint Pathology: Conditions, Diagnosis, and Management

Condition	Clinical Features	Diagnosis	Management
Midtarsal joint arthritis	Pain at talonavicular or calcaneocuboid joint; worse on uneven terrain; midfoot swelling; stiffness after rest; restricted midfoot motion; often follows Lisfranc injury, navicular fracture, or longstanding flat foot	Weight-bearing X-ray: joint space narrowing, osteophytes, subchondral sclerosis at talonavicular or calcaneocuboid joint; diagnostic injection confirms joint as pain source; CT for articular detail	Conservative: rocker-bottom shoe, rigid custom orthotic, corticosteroid injection, activity modification. Surgical: talonavicular arthrodesis (fusion) — highly effective but eliminates most midfoot motion; calcaneocuboid fusion for isolated lateral column arthritis
Navicular fracture	Dorsal navicular avulsion (most common — pulled off by tibionavicular ligament after forced plantarflexion); navicular body stress fracture (athletes — dorsal navicular pain with activity, tender on dorsal navicular palpation); high-energy navicular fracture (Sangeorzan classification, requires CT)	X-ray: avulsion visible on AP view; stress fractures often not visible until MRI or bone scan; CT for body fractures; MRI for stress response without visible fracture	Avulsion: boot 4-6 weeks. Navicular body stress fracture: non-weight-bearing cast 6-8 weeks (high non-union risk with early weight-bearing). Displaced fractures: ORIF to restore articular congruity and arch height
Cuboid syndrome	Lateral midfoot pain; often follows ankle inversion injury or overuse; pain at calcaneocuboid joint with peroneal longus tendon over cuboid tunnel; cuboid manipulation (whip manipulation) may be therapeutic and diagnostic	Clinical: lateral midfoot pain, pain with eversion against resistance, reproduction with direct pressure over cuboid; X-ray typically normal; MRI may show bone marrow edema at cuboid; ultrasound-guided injection diagnostic	Cuboid whip manipulation (manual therapy); peroneal stretching; lateral wedge orthotic; if recurrent: consider peroneal tendon evaluation for peroneus longus tear at the cuboid tunnel
Chopart amputation biomechanics	Amputation through the midtarsal joint (Chopart level) removes the forefoot while preserving the hindfoot; equinus deformity is the primary complication (unopposed Achilles with no forefoot lever arm)	Clinical assessment of residual limb; equinus deformity progressive without Achilles lengthening or tenotomy; prosthetic fitting required at Chopart level	Achilles lengthening at time of amputation or shortly after to prevent equinus contracture; prosthetic Chopart foot with extended toe plate restores some forefoot lever function; custom footwear essential

At Balance Foot & Ankle in Howell and Bloomfield Township, midtarsal joint assessment — including talonavicular and calcaneocuboid palpation, midfoot range of motion, and spring ligament stress testing — is integrated into every acquired flat foot evaluation, because the transition from PTT dysfunction to spring ligament failure to midtarsal joint arthrosis determines whether surgical reconstruction is possible or whether arthrodesis is required. Call (810) 206-1402.